萘降解质粒pND6-1中萘趋化基因nahY的克隆和核苷酸序列分析

CLONING AND NUCLEOTIDE SEQUENCE ANALYSIS OF NAPHTHALENE CHEMOTAXIS GENE nahY IN NAPHTHALENE-DEGRADING PLASMID pND6-1

假单胞菌 (Pseudomonas)ND6菌株的萘降解基因位于 10 2kb的质粒 pND6 1上 .以pUC18质粒为载体 ,制备了含有 1.5～ 3 .0kbpND6 1DNA随机片段的基因文库 .通过DNA测序和DNA序列的同源性分析 ,从基因文库中筛选出含有萘趋化基因nahY的克隆 .nahY基因的大小为 16 17bp ,编码的萘趋化蛋白由 5 38个氨基酸组成 ,与假单胞菌G7菌株的nahY基因相比 ,核苷酸序列的同源性是 96 .7% ,编码的氨基酸序列的同源性是 95 % .图 4参

Naphthalene-degrading genes of Pseudomonas sp. strain ND6 were localized to the 102 kb plasmid, pND6-1. Using pUC18 as a vector, a gene library containing 1.5～3.0 kb of DNA fragments from pND6-1 was constructed. By means of sequencing and analogous analysis of DNA fragments cloned, a clone containing naphthalene chemotaxis gene, nahY, was selected. The size of nahY gene from pND6-1 is 1 617 bp, which encodes 538-amino-acid chemotaxis protein. In comparison with nahY of Pseudomonas strain G7, their homology of nucleotide sequences is 96.7% and the homology of amino acid sequences is 95%. Fig 4, Ref 7